In the manufacturing process, a waste particle may be formed. For example, in the operation of a punch press, a punch interacts with a die to form a hole in a workpiece. The resultant slug cut from the workpiece is a waste particle which needs to be removed from the work area. If not removed, the slugs can contaminate the workpiece or work area, or hang up in the punch press. Preferably, the slugs are transferred to a remote area where they can be collected and removed, thereby freeing the operator for other duties.
In the manufacturing of webs of flexible material (for example, photosensitive paper and film), waste particles such as edge trimmings and hole punchings, may be generated during the operations of chopping, cutting, slitting, punching, and packaging. If not removed, the waste particles can contaminate the final product. Such waste particles are often difficult to collect because they are flexible, small, lightweight, and contain microscopic debris. Further, because the manufacturing operation can be continuous, there may be numerous locations (i.e., sources) wherein waste particles are simultaneously being formed.
Vacuum has been used to suction and remove waste particles. U.S. Pat. No. 4,759,246 (Herrington) teaches the use of a suction device for aspirating the punched-out portions of a film web to a waste disposal. Similarly, U.S. Pat. No. 4,779,397 (Christine), U.S. Pat. No. 3,800,643 (Scott), and U.S. Pat. No. 3,654,829 (Anderson) teach a punch press apparatus employing vacuum to suck slugs into a collection bin. U.S. Pat. No. 5,205,847 (Montieth) relates to an air cleaning apparatus wherein air and scrap pieces of material are directed into a rotating perforated drum. A high velocity jet of air transfers the scrap pieces into a hopper.
When waste particles are transferred from a plurality of locations/sources to a single collection hopper, the vacuum levels at each particle waste source may not be uniform, particularly if the collection hopper is located remotely. Nonuniform vacuum levels can adversely affect the manufacturing process. For example, vacuum fluctuations can result in obstructions in the removal system and inconsistent quality levels of a manufactured product.
Accordingly, a need continues to exist for an evacuation apparatus wherein independent vacuum level control is provided at each particle waste source so that a uniform vacuum level can be obtained to remove waste particles from a plurality of sources. Such an apparatus must be robust to continuously operate in a manufacturing environment, and must be suitable for flexible web material such as photosensitive film and paper. Further, the apparatus should provide an economical and safe method of removing waste particles, promote a quality manufactured product, and have minimal impact on the manufacturing process.